Hello,

I’ve bought a Corvette C3 1981(not the smartest choice btw), but I am seeing it as a new challenge. So after buying the car, it went well for 60 miles and then the problems started.

I have the L81 engine, with the quadrajet Rochester. I swapped it to a Edelbrock. The new carburetor starts pretty well, but when I am full gas, the carburetor starts poping or something like that. I started reading in forums and I learned that the carburetor needs a recalibration, even it is calibrated from factory. I tried to do this and after some miles it started again. For a period of time this problem occured when popping the lights up.

I also read that the distributor should be changed. And if it is to be changed, which one?

I really want to get it done, because I’m trying to repair for one and a half years now.

Any info would be appreciated.


Thanks

 

If you used the stock intake and bolted an adapter......that is a large portion of the problem.....the other part is that the ECM is no longer controlling timing since you removed the original carb........so yes, you need a new distributor.
So this is your problem with the carb:

See the two blue circles? They are partially blocking off airflow that is crucially needed for proper fuel metering......you cannot tune this carb out to run correctly on this adapter.

You have three options:

1) Have the original carb refurbished and reinstall......this will assume that the rest of your setup is untouched and functioning......DO NOT buy a refurbished unit......have it done by a Pro Carb builder......unfortunately, our Q-Jet expert here, Lars, does not service these carbs as he has no way to test an electronic one......pretty much no one does. Anyone that refurbishes it will be guessing on their finished product if it functions the way it should.......the carb is a 4ME, it is not like other Q-Jets, it is computer controlled....and only came one year on Corvette, 81-88 on other GM applications....the last carbureted car ever produced (1988 SS Monte Carlo) had this carb......my personally opinion is that they are troublesome and not worth repairing......and spare parts will not be available forever.
2) Convert the car to Pre-1981 specs......this is a very common mod......and relatively simple, all you need is a Pre-1981 Q-Jet for Chevrolet V8....and a Pre-1981 distributor.....the carb would be a nice core found on E-Bay and sent to someone like Lars.....the distributors are available new in the aftermarket. Right now with the carb disconnected.....the engine has zero ignition curve, and this is important.
3) Install a 2101 Edelbrock Performer intake........this option will also require a new distributor......but the carb can freely flow with this intake and function as intended......if you have never done one, this should be performed by a skilled technician.

I recommend option #2...and if you had your car at my shop...this would be the way to go......I would also clean up all the vacuum lines and remove the smog equipment.......

Jebby

 

Thank you very much for the quick reply!

Since I have already bought a new carb, I think I will go for option no. 3. I googled up a new intake, the 2101 Edelbrock Performer intake you suggested, and I found it around $200-$250. If I buy this and get a new distributor, will it be all I have to do ?

Alex

 

You will need intake gaskets (Fel Pro 1204) bolts (ARP 12pt or similar)......but yes, once the intake and distributor is installed...timing will need to be set, and idle mixture......from there that is the best it is going to get if there are no underlying issues....the new intake will be non-EGR...that is fine.....toss it.

Jebby

 

I'd really like to know where the "Edelbrock 1406 solves all problems" myth got started. My wife heard it when we bought her 79. It is absolutely not true.

I have a CCC delete kit for sale that (with a rebuild that you or someone else performs) will solve your issue, too. Can you return the carb that you bought?

https://www.corvetteforum.com/forums...nd-intake.html

 

Hello,

Unfortunately I don't have any chance returning it. This carb is all I got, and as for the old one(Rochester), I don't think I have all the components anymore.

My c3 corvette, has a L81 engine, the car comes from California. I recently found out that the California models had got some modifications back then. So when I started this swapping, my old carb had a lot of vacuums attached to it. My engine was making about 190HP back then, which I didn't like so much. So this is one reason why I went for the Edelbrock. I want to make my engine as clean as possible. The CCC removal is next on my list.


Alex

 

You really should seriously consider option 2, but I have a nice Weiand Stealth AirStrike intake that would sit well under that carb.

 

The Weiand is a good piece…..

Jebby